It's a tail-dragger and the tank is directly in line with the engine so if anything it should be around the same height as the carburetor. I also had a problem with it not cutting off when I shut the throttle. Upon closer inspection I found that the carburetor was not seated all the way down and there was a gap at the O-ring. This explained why it wouldn't shut off and once seated I was able to tune it properly. I like the simplicity of these engines and fixing them can be easy, you just have to look out for the little things.